Gaseous electric discharge device



Nov. l2, 1935. H. A. w. KLINKHAMER' ET Al. 2,020,786

GASEOUS ELECTRIC DISCHARGE DEVICE` Filed Dec. 1, 1932 (/Zari e ruz'n, Iziz'zzafzdus l UZ. van 'efelelz burg,

Patented Nov. `12, 1935 UNITED STATES PATENT OFFICE GASEOUS ELECTRIC DISCHARGE DEVICE Application December 1, 1932, Serial No. 645,283 In the Netherlands December 1, 1931` 3 Claims.

The present invention relates generally to gaseous electric discharge devices and more particularly the invention relates to starting and operating circuits for a plurality of such devices.

s The object of the invention is to provide a gaseous electric discharge devices.

gaseous electric discharge devices are used to il-A luminate large outdoor areas, such as roads or the like. A further object of the invention is to .v provide an illuminating system for outdoor lighting of greater efllciency than the present systems using incandescent lamps. Still further objects and advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from the following particular description and from the appended claims.

The invention attains its objects by using a plurality of gaseous electric discharge lamp devices each having a thermionic electrode and filled with a gaseous atmosphere comprising a metal vapor, such as sodium vapor and a plurality of series connected transformers one for each of said devices. is particularly advantageous to use auto-transformers in such a circuit especially where the gaseous electric discharge lamp devices are provided with two thermionic electrodes which are connected to the respective ends of the autotransformer. In special cases it is desirable to connect one of the current supply leads of the auto-transformer at a part thereof between the ends of said transformer.

Our invention will be described more fully in connection with the accompanying drawing in Fig. 1 is a schematic view of one embodiment of our invention,

Fig. 2 is a similar view of another embodiment ofv our invention, and

Fig. 3 is a similar view of another embodiment of the invention.

InfFig. 1 of the drawing a plurality of gaseous electric discharge lamp devices is illustrated, each device comprising a container I having two anodes 3 and a thermionic cathode 2 sealed therein. Each of said containers I is filled with a rare gas, a metal vapor, or a mixture of rare gas, such as neon, and a metal vapor, such as sodium. The cathode 2 of each of said devices is a fllamentary cathode of nickel Wire, for example, coated with electron emitting material, such as barium oxide. Each of said anodes 3 of said devices is connected We have discovered that itthrough a resistance 4 to the secondary 5 of a transformer 5, l. Said cathodes 2 are connected to said secondary 5, near the mid-point thereof, by leads 6. The primaries l of said transformers 5, 'I are connected in series to the secondary of `il transformer 8. The primary of said transformer 8 is connected to the terminals of a high voltage alternating current source.

When switch I8 is closed the cathodes 2 are quickly heated to an electron emitting tempera.- l ture and the discharge starts. between said electrodes 2 and 3 in each of said devices at approximately the same time. As the voltage required to start the devices into operation is higher than the voltage required to maintain the devices in operation the resistances 4 are provided to absorb the excess voltage supplied during the operation of the device. It is advantageous to arrange said resistances 4 in close proximity to said containers I so that the heat developed therein is utilized to maintain the sodium vapor pressure in said containers I.

The embodiment of the invention illustrated in Fig. 2 is even more eiiicient and inexpensive than that illustrated in Fig. 1. In this embodiment an auto-transformer 9 is used in place of the transformer 5, 1 of Fig. 1. The auto-transformers 9, 9 regulate the distribution of voltage between the electric discharge devices and are less costly to manufacture than the type of transformer illustrated in Fig. 1. The discharge devices illustrated in Fig. 2 have two thermionic electrodes II,`I2, one sealed into each end of the container I0. The part II of said electrodes I I, I2 is a metal filament, such as a nickel filament, coated with electron emitting material, such as barium oxide, and is electron emitting when heated and part I2 of said electrodes II, I2 is a metal cylinder surrounding said part Il. Said parts II and I2 are electrically connected to each other by lead 20, as illustrated, and during the operation of the device part II acts as the cathode and part I2 as the anode. Two current supply leads connect each of said electrodes Il, l2 to an auto-transformer 9. One lead of each pair is connected to one 4,5 of the ends of said transformer 9 and the other lead of each pair is connected to a tap I5 or I6 on the coil of said transformer 9. 'Ihe autotransformers 9, 9, are connected in series with the secondary of transformer I4 and the primary 50 of said transformer I4 is connected to the terminals of an alternating current source. A resistance I3 is connected into the leads connecting said transformers 9 in series and to the secondary of said transformer I4.

Those parts of said transformer 9 between points I5 and I6 and the respective ends thereof supply the heating current for said electron emitting cathodes II during the starting and operating of the device. When current is first applied to the device said electrodes II are promptly brought to an electron emitting temperature, and, as soon as sufcient electrons have been emitted into the discharge path between said electrodes II, I2 the discharge is established in the device. During the operation of the device the discharge alternates between the left anode I2 and the right cathode II and the right anode I2 and the left cathode I I which avoids overheating of said electrodes II, I2 during the operation of the device. By using an electron emitting electrode at each end of the device in connection with an autotransformer 9 it is possible to make that part of said auto-transformer 9 located between the taps I5 and I6 of finer and less expensive wire than was practical heretofore as said part is not traversedby the operating current of the device but only by the magnetizing and heating currents. This affects a considerable saving in the manufacturing cost of said transformers 9, 9.

The use of auto-transformers in such a system has another advantageous feature in that where one of the discharge devices starts later than the others a higher current flow takes place through the auto-transformer for said slow starting device which induces a higher voltage between the ends of said transformer which facilitates the starting of the device.

The illuminating system illustrated in Fig. 2 is particularly useful in illuminating large areas. Where the discharge lamp devices have a sodium vapor filling, or a gaseous lling comprising sodium, and a starting voltage of 17.5 Volts approximately 28 electric discharge lamp devices can be connected into the circuit where the secondary of transformer I4 supplies 500 volts. It is suiiicient if the voltage supplied by the secondary of transformer I4 is slightly greater than the product of the number of lamp devices multiplied by the operating voltage of said lamp devices but said voltage need not be as great as the product of the number of lamps multiplied by the starting voltage of said lamp devices. This follows from the fact already stated that when one lamp has started the potential on the lamps which have not yet started is increased which facilitates the starting of said slow-starting lamps.

In many cases it will be possible to utilize a three-phase system and successive lamp devices are connected to different phases. In such cases the three-phase current supply system has or has not a neutral, as desired. It is obvious that larger areas can be illuminated with a normal voltage by using a three-phase current supply system.

It is advantageous to bridge each transformer by a resistance connected in parallel therewith. During the normal starting and operation of the lamp device said resistance is out of circuit but if the device becomes inoperative for any reason the resistance is cut into the circuit. The complete breakdown of the illuminating system due to the failure of one lamp device is thus avoided. Well known automatic means controlled by the change in voltage in auto-transformer 9 is used to cut into the circuit said resistance on the failure of the lamp device connected to said transformer.

The number of lamp devices in the system can be increased or decreased without changing the voltage supplied by the secondary of the transformer 8 or I4 provided a plurality of taps I1 to which at least one of the current supply leads can be connected are provided von the transformers for said lamp devices as illustrated in Fig. 3. The voltage on each lamp device can thus be 10 maintained independently of the number of lamp devices connected into the circuit, within reasonable limits of course.

What we claim as new and desire to secure by Letters Patent of the United States is:

l. An illuminating system comprising a plurality of gaseous electric discharge lamp devices at least one of the electrodes thereof being a thermionic electrode comprising a filament and an electron emitting oxide body heated thereby, a plurality of series connected transformers, one for each of said devices, and a current source 'for said transformers, the voltage of said current source being greater than the product of the number of lamp devices multiplied by the operating voltage of said lamp devices and less than. the product of the number of lamp devices multiplied by the starting voltage of said devices whereby the starting of one lamp of the series increases the voltage applied to a slower starting lamp to insure the starting thereof.

2. An illuminating system comprising a plurality of gaseous electric discharge lamp devices having therein a gaseous atmosphere comprising sodium and at least one of the electrodes thereof being a thermionic electrode comprising a filament and an electron emitting oxide body heated thereby, a plurality of series connected autotransformers, one for each of said devices, and a current source for said auto-transformers, the voltage of said current source being greater than the product of the number of lamp devices multiplied by the operating voltage of said lamp devices and less than the product of the number of lamp devices multiplied by the starting voltage of said devices whereby the starting of one lamp of the series increases the voltage applied to a. slower starting lamp to insure the starting thereof.

3. An illuminating system comprising a plurality of gaseous electric discharge lamp devices having therein a sodium vapor filling and at least one of the electrodes thereof being a thermionic electrode comprising a filament and an electron emitting oxide body heated thereby, a plurality of series connected current and potential changing devices, one for each of said lamp devices,

' and a current source for said current and potential changing devices, the voltage of said current source being greater than the product of the number of lamp devices multiplied by the operating voltage of said lamp devices and less than the product of the number of lamp devices multiplied by the starting voltage of said devices whereby the starting of one lamp of the series increases the voltage applied to a slower starting lamp to insure the starting thereof. HENDRIK A. W. KLINKHAMER.

AART DE BRUIN.

FERDINANDUS H. A. VAN STEKELENBURG. 

